I have had my Fenix 5 for a few weeks ago and have been observing incorrect Elevation Gain data from day 1.
My rides take place on very familiar hilly territory that I have been capturing usually every 2 or 3 days, with my ultra reliable 10 year old Garmin Edge 500, and I have been using the Edge 500 as a backup device to the Fenix for my rides.
I have noticed that the Fenix underestimates the Elevation Gain by roughly 10%. My testing involves creating a data screen on the Fenix showing Altitude, Elevation Gain and GPS Altitude and on the Edge 500 I have Elevation, and Total Elevation.
From this setup I am confident that the Altitude on the Fenix is correct as it shows the correct elevation while on the top of several mountains with clear sky and no building or trees within 100's of meters. It also matches the Altitude on the Edge 500.
What I have now noticed and confirmed over and over is that the Fenix often ignores the first few meters on a climb and sometimes the last few meters of a climb. For example if I click a hill starting at 100 meters the Fenix would show:
Altitude = 100, Elevation Gain = 0
Altitude = 101, Elevation Gain = 0
Altitude = 102, Elevation Gain = 0
Altitude = 103, Elevation Gain = 1
Altitude = 104, Elevation Gain = 2
Altitude = 105, Elevation Gain = 3
.......
Altitude = 196, Elevation Gain = 93
Altitude = 197, Elevation Gain = 94
Altitude = 198, Elevation Gain = 94
Altitude = 199, Elevation Gain = 94
Altitude = 200, Elevation Gain = 94
Altitude = 200, Elevation Gain = 94
So total for the Fenix would be 94m, and the Edge would correctly show 100m.
At the bottom my road is a short ramp that is about 4 meters high and need a good climb out of the saddle to keep your speed up over it. It remains at the same level after the ramp for a long way. The Fenix sees this as a 2m Elevation Gain and the Edge 500 correctly sees this as a 4m gain.
I chose the Fenix 5 specifically because it had a barometer and there was a considerable price increase for this feature. Anyone else seeing this and can this be fixed? The looks to me like either a bug or I wonder if the Elevation Gain algorithm uses an aggressive hysteresis to ignore small changes in Altitude that would be more suited to a Hiking data collection profile.
FW 13.30.0.0 set to log every second, GPS+Glonlass, calibrate Altitude from GPS. I should also say that I have followed all of the Garmin Support advice on this.
Attached below are images of my last ride from today where the Fenix reports 959m and the Edge 500 reports 1031m - a difference of 72m!
